Localisation of aphidicolin-induced break points in Holstein-Friesian cattle (Bos taurus) using RBG-banding

Abstract

-Fragile sites (FS) seem to play a role in genome instability and may be involved in karyotype evolution and chromosome aberrations. The majority of common fragile sites are induced by aphidicolin. Aphidicolin was used at two different concentrations (0.15 and 0.30 µM) to study the occurrence of FS in the cattle karyotype. In this paper, a map of aphidicolin induced break points and fragile sites in cattle chromosomes was constructed. The statistical analysis indicated that any band with three or more breaks was significantly damaged (P < 0.05). According to this result, 30 of the 72 different break points observed were scored as fragile sites. The Pearson correlation test showed a positive association between chromosome length and the number of fragile sites (r = 0.54). On the contrary, 21 FS were identified on negative R bands while 9 FS were located on positive R bands.cattle / chromosome / fragile sites / aphidicolin

Chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo <i>(Bubalus bubalis)</i>

“…0.01). This is in contrast with previous observations in pigs by Riggs et al (1993) and in cattle by Rodriguez et al (2002) who reported variations among animals due to an 'animal effect' rather than by gender. In the present study, the yield of breakages per chromosome was found to be significantly different 'among' the chromosomes within the karyotype thus indicating a 'nonrandom' expression.…”

“…By comparing the present results with those reported in cattle by Rodriguez et al (2002), obtained under the same experimental conditions, we observe a complete lack of homology in the location of fragile sites between the two species. While in river buffalo the most fragile band has been found on chromosome 9q213 with 24 breakages out of 400 (6%), followed by chromosome 19q21 with 16 (4%), chromosome 17q21 and inacXq24 with 15 (3.75%), in cattle the most fragile bands have been found in totally different non-homologous chromosomes, such as 1q13 and Xq31, with 14 breakages out of 217 (6.45%), followed by chromosome 1q21 with 11 (5.0%), 3q22 and 5q32 with 9 (4.1%).…”

“…Unlike the study reported by Rodriguez et al (2002), breakages were never observed on RBG positive bands. Such a discrepancy might be attributed to the lower level of banding resolution used in that study: in fact, in more contracted chromosomes, a large positive band may hide two or more sub-bands separated by negative bands where the breakage may occur.…”

“…Conventional lymphocyte cultures were performed (De Grouchy and Roubin, 1965): after 48 h of culture, aphidicolin (APD) (Sigma, St. Louis, USA) was added to the cultures at a final concentration of 0.15 M as recommended by Rodriguez et al (2002) and further incubated for 24 h. Six hours before the end of incubation, BrdU and H33258 (20 g/ml each) (Sigma) were added to the cultures to label late replicating regions of the genome. For each animal a 'control' culture without aphidicolin addition was performed.…”

“…While a conspicuous bulk of research has been conducted in humans, domestic animals have received only little attention. Cattle are the most investigated domestic species (Rodriguez et al, 2002), followed by pig (Ronne, 1995), rabbit Abstract. The present study reports on the chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo ( Bubalus bubalis , 2n = 50) with the aim of establishing a 'fragile site map' of the species.…”